issue 107 sept 2012
Petroleum potential of the Arrowie and Georgina basinsDeep seismic reflection data supports petroleum systems maturation modelling Lidena Carr, Russell Korsch and Heike Struckmeyer
Petroleum potential of the Arrowie and Georgina basins www.ga.gov.au/ausgeonews/ | 1
In 2006 the Australian Government expanded Geoscience Australia’s
program of seismic acquisition, data enhancement and client access
through the commitment of almost $134 million over five years to the
Energy Security Initiative.
The focus of the Onshore
Energy Security Program (OESP)
was to stimulate exploration
for energy resources, including
non renewable resources such
as hydrocarbons, uranium and
thorium as well as renewable
geothermal energy resources. The
OESP was carried out under the
National Geoscience Agreement
between the Australian, state and
Northern Territory governments.
As part of the OESP, deep seismic
reflection data were acquired across
several frontier sedimentary basins
to stimulate petroleum exploration.
This article reports on the
interpretation of the deep seismic
reflection profiles from the Arrowie
Basin in South Australia and the
Burke River Structural Zone of
the Georgina Basin in northwest
Queensland. The research
focussed on their stratigraphic and
structural architecture and was
consequently utilised in petroleum
systems maturation modelling to
increase the understanding of their
petroleum potential.
Arrowie Basin, south Australia
In 2008 Geoscience Australia,
in conjunction with Primary
Industries and Resources South
Australia (PIRSA), acquired a
Figure 1. Map showing the locations of seismic lines 08GA-A1 across the Arrowie Basin in South Australia and 06GA-M6 across the Burke River Structural Zone in Queensland.
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Petroleum potential of the Arrowie and Georgina basins www.ga.gov.au/ausgeonews/ | 2
60 kilometre long deep seismic line (08GA-A1) across the western
part of the Arrowie Basin, immediately to the west of the central
Flinders Ranges (Figure 1). This part of the basin has received
almost no attention for hydrocarbon exploration since the shallow
Wilkatana 1 well was drilled in the 1950s, to a maximum depth
of 670 metres. Some of these wells located 15 kilometres to the
south of the seismic line encountered non-commercial bituminous
hydrocarbons in the Cambrian succession (SANTOS 1957).
Petroleum systems maturation modelling in the Arrowie Basin was
carried out using the interpretation of stratigraphy and architecture of
seismic line 08GA-A1. A full description of the parameters used for
the modelling is included in Carr et al. (2012).
Georgina Basin, Northwest Queensland: Burke River structural Zone
In 2006 Geoscience Australia, in conjunction with the Geological
Survey of Queensland, the Predictive Mineral Discovery Cooperative
Research Centre and Zinifex Limited, acquired a 283 kilometre long
deep seismic reflection transect (06GA-M6) across the Burke River
Structural Zone of the Georgina Basin in northwestern Queensland
(Figure 1). This line was part of a larger, ~900 kilometre long seismic
survey across the Mount Isa Province (Hutton and Korsch 2008).
Only limited exploration has occurred in this region although the
southern Georgina Basin is considered to be a significant potential
hydrocarbon region, and includes a largely unexplored Middle
Cambrian petroleum system (Ambrose et al. 2001; Boreham and
Ambrose 2007).
Following the discovery of hydrocarbon indicators in water bores
drilled into the Cambrian succession, exploration has included several
petroleum exploration wells. Although there were numerous oil and
gas shows and solid bitumen has been recovered from drillcore (Volk
et al 2007) the wells proved unsuccessful for hydrocarbons (Ambrose
et al. 2001). Draper (2007) suggested that an early Paleozoic
carbonate petroleum system was present in the Georgina Basin in
Queensland, and he considered that, although the Toko Syncline is
more prospective, the Burke River Structural Zone is still worthy of
further exploration. The Georgina Basin has been the subject of recent
exploration, for both unconventional and conventional hydrocarbons,
including the drilling of the Macintyre 2 well within the basin
(Baraka Energy and Resources 2011). Petroleum systems maturation
modelling in the Georgina Basin was conducted utilising information
from the interpretation of the stratigraphy and architecture of seismic
line 06GA-M6. A full description of the input parameters and
modelling are available in Carr et al. (2012).
Results
The Arrowie Basin seismic data show an asymmetrical basin architecture, with the basin attaining a maximum depth of ~3800 metres. Several sequence boundaries mapped in this seismic section are correlated with the sequence boundaries between the major Neoproterozoic stratigraphic groups in the Adelaide Rift System. In the eastern most part of the seismic section a series of east-dipping thrust faults disrupt the stratigraphic section.
Petroleum systems maturation modelling conducted in the Arrowie Basin indicates that the generation and expulsion of hydrocarbons from mature source rocks occurred early during the burial history, and mostly prior to the Late Cambrian, consistent with previous findings (Figure 2). Potential Cambrian source rocks are probably immature to mature for oil generation at the modelled site in the basin. In contrast, potential Neoproterozoic source rocks are likely to be mature to overmature for oil generation, and immature to mature for gas generation. With hydrocarbon systems clearly present in the Arrowie Basin, future work, possibly with a focus on unconventional Cambrian hydrocarbons, is warranted.
Seismic data across the Burke River Structural Zone of the Georgina Basin show that the basin is about 65 kilometres wide, with a half graben geometry, being bounded in the west by a
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Petroleum potential of the Arrowie and Georgina basins www.ga.gov.au/ausgeonews/ | 3
rift border fault. The basinal succession attains a maximum thickness
of ~2800 metres, with the stratigraphy being relatively flat-lying and
thickening towards the basin bounding fault. Petroleum systems
maturation modelling for the Burke River Structural Zone indicates
that potential Cambrian source rocks are likely to be oil mature.
Significant generation and expulsion probably occurred early in the
burial history in response to
Cambrian-Ordovician loading.
Expulsion occurred after trap
formation in the Neoproterozoic-
Cambrian but before later trap
formation in the Devonian. The
Figure 2. Results from petroleum systems maturation modelling in the Arrowie Basin showing: a) burial history plot modelled with rapid late Proterozoic and Cambrian burial and minor uplift in the last five million years; b) predicted porosity versus depth.
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required long preservation time and unroofing are the major risk factors within the basin.
The main outcomes of the OESP have been the collection, interpretation and delivery of precompetitive data, significantly improving knowledge about Australian onshore frontier basins. This work has assisted in identifying the types of potential petroleum exploration targets to be expected in the onshore basins, and reducing exploration risk. It also provides baseline information for the future assessment of conventional and unconventional petroleum resources in Australia.
References
Ambrose GJ, Kruse PD & Putnam PE. 2001. Geology and hydrocarbon potential of the southern Georgina Basin, Australia. APPEA Journal 41: 139–163.
Baraka Energy and Resources. 2011. ASX Announcement: Elevated Hydrocarbon Shows Recorded from MacIntyre-2, Southern Georgina Basin, Australia. Available at: www.barakaenergy.com.au/announcements.php (accessed: December 2011).
Boreham CJ & Ambrose GJ. 2007. Cambrian petroleum systems in the southern Georgina Basin, Northern Territory, Australia. In Munson TJ & Ambrose GJ (eds). Proceedings of the Central Australian Basins Symposium, Alice Springs, 16-18th August, 2005. Northern Territory Geological Survey, Special Publication 2: 254–281.
Carr LK, Korsch RJ, Struckmeyer H, Jones LEA, Holzschuh J, Costelloe RD & Meixner AJ. 2012. The architecture and petroleum potential of Australia’s onshore sedimentary basins from deep seismic reflection data and petroleum systems maturation modelling: the Arrowie, Georgina and Darling Basins. Geoscience Australia Record 2012/36.
Draper J. 2007. Georgina Basin – an early Palaeozoic carbonate petroleum system in Queensland. APPEA Journal 47: 105–124.
Hutton LJ & Korsch RJ. 2008. Deep seismic reflection interpretations, Mount Isa and Isa-Georgetown surveys. In Digging Deeper 6 Seminar Extended Abstracts. Queensland Geological Record 2008/06.
SANTOS. 1957. Arrowie Basin: Wilkatana Well Completion Report numbers 1-19b. Primary Industry and Resources South Australia Open File Envelope No. 8577.
Volk H, George SC, Kempton RH, Liu K, Ahmed M & Ambrose GJ. 2007. Petroleum migration in the Georgina Basin: Evidence from the geochemistry of oil inclusions. In
In Munson TJ & Ambrose GJ (eds). Proceedings of the Central Australian Basins Symposium, Alice Springs, 16–18 August, 2005. Northern Territory Geological Survey, Special Publication 2: 282–303.
This work was presented at the Central Australian Basin Symposium on the 16 and 17 July, in Alice Springs.
Related articles/websitesThe architecture and petroleum potential of Australia’s onshore sedimentary basins from deep seismic reflection data and petroleum systems maturation modelling: the Arrowie, Georgina and Darling Basins (Geoscience Australia Record 2012/36).
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